Skin disorders are common afflictions for many people. Some of the most common are dermatitis (also known as eczema) and psoriasis. Dermatitis or eczema are synonymous terms used to define an inflammatory skin reaction characterized histologically by spongiosis with varying degrees of acanthosis, and a superficial perivascular lymphohistiocytic infiltrate. It is a common skin condition affecting significant populations in industrial countries. It is particularly prevalent on the hands of workers in service industry because of the workers frequent contact with wet or irritating chemicals. It is also hereditary in many instances. Psoriasis is a common auto-immune skin disease. Both dermatitis and psoriasis can cause serious physical and/or psychological suffering to the subject regardless of the location on the body that these conditions occur, but they are particularly bothersome if they occur on the skin of the hand. Those afflicted with such disorders often have to use their hands in their work which can aggravate the condition.
Various therapies are available to treat dermatitis or psoriasis. Preventive measures including avoiding wet work and wearing recommended gloves, followed by topical treatment as the first line of therapy for acute and sub-acute cases. Several classes of topical drugs are available and are most frequently found in the form of creams, gels, or ointments. These drugs include corticosteroids such as betamethasone dipropionate, clobetasol propionate, halobetasol propionate, diflorasone diacetate, amcinonide, desoximethasone, fluocinonide, halcinonide, mometasone furoate, betamethasone valerate, fluocinonide, fluticasone propionate, triamcinolone acetonide, fluocinolone acetonide, flurandrenolide, desonide, hydrocortisone butyrate, hydrocortisone valerate, alclometasone dipropionate, flumethasone pivolate, hydrocortisone, and hydrocortisone acetate; immune system modulators such as tacrolimus and picrolimus; vitamin D3 and its analogs such as cholecalciferol, calcitriol, calcipotriol, and tacalcitol; and retinoic acids or their derivatives such as tazarotene. Persistent cases are often treated with oral corticosteroids such as prednisone, while chronic recalcitrant cases that cannot be controlled by topical or systemic corticosteroids are treated with light therapy in the form of PUVA carried out by ingestion of 8-methoxyproralen or by UV-B treatment.
Unfortunately, current therapies have many drawbacks. Oral medications frequently have undesirable side effects. Topically applied ointments and gel medications can be unintentionally removed from the treatment area when the skin is contacted by other objects. In addition, topically applied medications may spread onto surrounding healthy skin areas and cause undesirable adverse side effects including atrophy of healthy skin by exposure to corticosteroids, compromised immune system due to unnecessary contact by immune modulator drugs to large healthy skin areas, and irritation of healthy skin areas by retinoic acids or their derivatives. Dermal (including transdermal) patch dosage forms also are available in a few different forms, including matrix patch configurations and liquid reservoir patch configurations. In a matrix patch, the active drug is mixed in an adhesive that is coated on a backing film. Dermal (including transdermal) patch dosage forms also are available in a few different forms, including matrix patch configurations and liquid reservoir patch configurations. In a matrix patch, the active drug is mixed in an adhesive that is coated on a backing film. The drug-laced adhesive layer is typically directly applied onto the skin and serves both as means for affixing the patch to the skin and as a reservoir or vehicle for facilitating delivery of the drug. Conversely, in a liquid reservoir patch, the drug is typically incorporated into a solvent system which is held by a thin bag, which can be a thin flexible container. The thin bag can include a permeable or semi-permeable membrane surface that is coated with an adhesive for affixing the membrane to the skin. A shortcoming of dermal (including transdermal) patches is that they are usually neither stretchable nor flexible, as the backing film (in matrix patches) and the thin fluid bag (in reservoir patches) are typically made of polyethylene or polyester, both of which are relatively non-stretchable materials. If the patch is applied to a skin area that is significantly stretched during body movements, such as a joint, separation between the patch and skin may occur thereby compromising the delivery of the drug. In addition, a patch present on a skin surface may hinder the expansion of the skin during body movements and cause discomfort. Therefore, it would be desirable to have a topical formulation that is easy to apply, stays on the diseased skin area, and delivers the active drug continuously. It would also be desirable to have a formulation that is resistant to removal from the treatment site and can be confined spreading onto skin outside the intended to treatment area.